I tried ${artifact.FullyQualifiedName}.xsd
And it did not work.
It seems that only something like this will do:
${artifact.Package}_${artifact.Name}.xsd

I guess (I tried it) calling a method of a defined Velocity Context
Definition does not work as well.

So, can I have a confirmation that today I have no chance on having any
programmatic controls over the naming of generated files over than using
those documented parameters?

I want to be able to generate a file for each packages of my project
(natively defined and from dependencies). I think the easiest way would be
to use a Plugin Artifact Rule associated with the Package artifact type.
But, I want to have more control over the naming.
Any other suggestions?